查看更多>>摘要：Pre-oxidation have been widely applied in drinking water treatment plants with micro-polluted water as water sources. In this study, the effects of three commonly used oxidants (ozone, chlorine, and potassium permanganate) on disinfection by-products (DBPs) formation from micro-polluted water during subsequent chlorination and chloramination were investigated. Moreover, the toxicities of treated water were also compared. In addition, principal component analysis was applied to clarify the main components that contributed to DBPs generation. The results demonstrated that all the selected oxidants could reduce DBPs to some extent, but the species and amounts were quite different. Pre-KMnO4 greatly reduced haloacetic acid (HAAs) formation in subsequent chloramination; the removal rate reached up to 45.2%. Pre-HClO could produce trihalomethane (THMs) and HAAs directly, and its effect on DBPs reduction during subsequent disinfection processes was limited. Pre-O3 performed best on N, N-dimethyl nitrosamine (NDMA) reduction during subsequent chloramination; the corresponding removal rates were 49.7%. In addition, pre-O3 significantly reduced UV254 and SUVA. Pre-KMnO4 transferred more organic matter to cationic components (24%), while the highest polar component augmentation was observed during pre-HClO (15%). Based on the analysis of total toxicity of formed DBPs, pre-O3 performed best on toxicity reduction no matter subsequent chlorination or chloramination, which decreased by 25.8% and 46.4%, respectively. The principal component analysis showed that DBPs has a weak correlation with regular water quality parameters, but related with specific organic fractions. The results of this paper had significant guidance for the selection of pre-oxidation methods in drinking water treatment plants for this kind of water sources.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：The present work carries out a comparative study to illustrate the safety performance of two new-format cells (22650 and 26650) in the thermal runaway tests induced by over-heating and overcharge tests, referred by the traditional 18650 cells. In addition, a long-term cycling test is also performed to evaluate the electrochemical characteristics of the three cells. When charged to the same capacity (1700 mAh), the cell with a larger size demonstrates comparative gentler thermal runaway behaviors during the over-heating, with a longer time to thermal runway and a higher temperature to thermal runaway. The thermal runaway of the fully charged 26650 cell lags behind that of 18650 and 22650 cells in the over-heating tests; that is, the 26650 cell shows the best thermal safety performance among the three kinds of cells. The safety performance of the 26650 cell is also more competitive than 18650 and 22650 cells during overcharging, with a larger SOCend illustrated when the interior safety devices take effects. At last, the 26650 cell shows more promising electrochemical features, demonstrating a larger absolute capacity and a slighter degradation over the long-term cycling, in comparison with 18650 and 22650 cells. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Due to limited fossil fuel resources and greenhouse gas emissions, the use of biodiesel is increasing. In this study, biodiesel was produced from waste edible oil (WEO), as a low-cost oil, using MgO and MgO@CNT@K2CO3 catalysts. The MgO@CNT@K2CO3 catalyst was first synthesized in this study and used to produce biodiesel. To this end, the features of these catalysts were studied using FTIR, BET, XRD, EDX, SEM, and Map analyses. The results indicated that both catalysts have high catalytic activity with mesoporous structures. Due to the high content of free fatty acid (2.43 wt%) in WEO, a two-step transesterification process was used to convert WEO to biodiesel. In the first step, hydrochloric acid homogeneous catalyst was employed to reduce the FFA content and then in the second step, MgO and MgO@CNT@K2CO3 heterogeneous catalysts were used to generate biodiesel. The highest biodiesel yields using MgO and MgO@CNT@K2CO3 were 94.26% and 98.25%, respectively, which were achieved at a catalyst concentration of 4%, temperature of 65 ?degrees C, and methanol/oil ratio of 24:1 and 20:1 after 5 and 4 h for MgO and MgO@CNT@K2CO3 , respectively. The MgO@CNT@K2CO3 showed the highest biodiesel yield ever achieved from WEO. Also, the physical features of biodiesel were investigated and the results demonstrated that the biodiesel produced are in accordance with ASTM D6751 and EN14214 standards. Moreover, kinetic and thermodynamic studies showed that the transesterification reaction is endothermic and non-spontaneous. Therefore, MgO@CNT@K2CO3 is proposed as a strong and cost-effective catalyst for biodiesel generation from WEO on an industrial scale. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Compounds that are potential precursors of secondary organic -aerosols account for up to 33.4 +/- 7.1 mg/m(3 )in softwood combustion emissions, while biochar can be considered zero-emission fuel (0.18 +/- 0.06 mg/m(3)). The characteristic feature of gaseous emissions from biochar combustion is the presence of n-alkanes (70.3 +/- 6.6 mu g/m(3)), which arise from the thermal degradation of waxes, cuticles, and plant lipids. In addition to alkanes, carboxylic acids (4.9 +/- 0.2 mu g/m(3)) are present in biochar emissions at significantly lower concentrations. In deposits from biochar combustion (6.1 +/- 0.8 g/kg), the internal parts of the boiler capture 20% more organic compounds than in wood-burning deposits (4.84 +/- 0.91 g/kg). The greater uptake of organic compounds in biochar combustion deposits (513.8 +/- 6.2 g/kg) than in softwood (382.7 +/- 27.3 g/kg) is related to the higher elemental carbon content in biochar. The organic compounds present in deposits from biochar are mainly methyl ketone, fatty acids such and alkanes. In deposits from softwood, the compounds of chemical groups of phenols, anhydrosaccharides and acetic acids are present. The novelty lies in identifying and determining the quantity of organic compounds that form precursors of the solid organic aerosols in the combustion of biochar. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Leakage of methanol under negative pressure may cause high dangerous spray explosion in the process industry. The explosion characteristics of methanol spray under the combined effects of multi-factor have not yet been studied. Hence, combined effects of spray concentration (198.0-514.8 g/m(3)), ambient temperature (298.15-323.15 K) and injection pressure (13-21 bar) on atomization and spray explosion of methanol (308.15 K) in 20 L spherical vessel under negative pressure (0.80-1.0 0 bar) were studied in this paper. The results showed that the decrease of methanol concentration, the increase of ambient temperature and injection pressure all promoted the breakage of methanol spray with linear trend. Based on the negative pressure, the effect weights of concentration, ambient temperature, and injection pressure were 113.7 mu m/bara, 243.3 mu m/bara, 64.24 mu m/bara, respectively. The "peak plateau " of explosion temperature lasted for 237.6 ms due to the multi-point source ignition. In contrast to the explosion pressure change, the temperature of methanol spray slightly decreased in delayed ignition region. The increase of spray concentration provided more combustibles and contributed to the spray explosion when the methanol concentration was below 356.4 g/m(3). As the concentration continued to rise, the maximum explosion pressure under room pressure (0.1 bar) decreased inhibited by the poor oxygen, while the maximum explosion pressure under negative pressure (0.80-0.95 bar) slowly increased. The increase of ambient temperature promoted the maximum explosion pressure, temperature and the rate of pressure rise, especially the promotion under negative pressure, was more significant. The variation of the maximum explosion pressure and maximum rate of pressure rise was consistent with that of the spray particle size when influenced by injection pressure. The experimental results showed that the methanol spray was more explosive and dangerous under negative pressure.(C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Flow structures of non-swirling and swirling particle-laden turbulence are modeled using the large eddy simulation. Four-way coupling to reveal the interaction mechanism of gas to particle, particle to gas and particle-particle collisions is adopted by a new proposed subgrid scale (SGS) particle kinetic energy-granular temperature model. Evolution of particle vortices, particle coherent structures and particle dynamics are predicted numerically, and comparisons are also conducted. Predictions are in good agreement with experimental measurements. For non-swirling flows, the typical coherent structures, and larger vortices at downward region of gas flow are dominantly. However, particle transport characteristics are significantly different, distinctly coherent structures and more vortices have not been generated in additions to fewer ones at far distance from entrance. Meanwhile, fewer coherent structures and vortices that dispersed at corner recirculation are observed for swirling flow. Compared to gas flow, the number of particle vortices is less and Reynolds stress and kinetic energy transport behaviors of particle flow are relatively independent due to inertia. Gas fluctuations of shear stresses are approximately twice greater than those of particle in non-swirling flows. A novelty finding is that turbulent fluctuations and instantaneous gas vortices of non-swirling flow are stronger than swirling case. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Pavithra, S.Veeramani, T.Subha, S. SreeKumar, P. J. Sathish...
13页
查看更多>>摘要：A sincere effort has been made to engineer a perched cum off-centered wick solar still (PCWSS) in the present work. The daily average efficiency with hourly prediction distillate yield of the PCWSS has used those artificial neural networks (ANNs) tool with Harris Hawk's Optimizes (HHOs) technique. HHO performance with ANN simulated as an optimal parameter to grab preyed. An experimental performance predicting the system's productivity is associated by dual supplementary mockups as vectors gadget, tradition ANN. HHO-ANN approach results are compared with the experimental observations (one year) of the solar still. Radial Basis Function (RBF) and Feed Forward (FF) have been used ANN structures to estimate hourly distillate yield and efficiency of the system is 59.78%. Evaluating the R2, RMSE, MRE, MAE, EC, OI, CRM analysis of prediction models was based on numerical error conditions. Optimized the analysis of PCWSS with a model as HHO-ANN used optimal parameter values has prediction accuracy associated with ANN and the competence for HHO. Annual analysis based on the HHO - ANN structures predicted the hourly distillate yield with mean error varying from 8.13% and 6.1%. The error for the monthly average prediction of distillate yield is from 0.95% to 1.12%, respectively. HHO - ANN has been used with the best accuracy in predicting the PCWSS invention associated with tangible experimental outcomes. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：This paper investigated the environmental impact of leather from production phase via identifying the hazardous substances (such as HCHO, Cr[VI]), leaching toxicity and ecotoxicity, with special emphasis on chrome or chrome-free. The hazardous substances of concern in various tanned leather waste from processing and commercial product were found lower than the present criterion for the eco-label product, different from the leaching toxicity and ecotoxicity. Several of the chrome-leather samples might be classified as hazardous waste for total chrome leached beyond the limitation though no Cr(VI) was leached out. Whereas the ecotoxicity toward photobacterium phosphoreum of leather samples from technology flow indicated chrome-tanned samples (S1-S3) was more toxic than corresponding chrome-free samples (S4-S6), confirming the crucial environmental impact of the tanning procedure. The increased toxicity of finished leather (S3 and S6) also revealed the significance of the finishing procedure in developing environmentfriendly leather products. The multiple linear regression further demonstrated the positive correlations of the ecotoxicity of leather with leached total Cr, HCHO, and anionic polyelectrolyte. These results discerned the crucial procedures and chemicals to improve the process safety of leather. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Yuksekdag, AyseKose-Mutlu, BorteWiesner, Mark R.Koyuncu, Ismail...
11页
查看更多>>摘要：Pre-concentration and separation processes of Rare Earth Elements (REEs) were investigated in terms of several factors. Nitric acid leachate of e-waste was first pre-treated by increasing pH and filtering through microfiltration. For pre-concentration, pre-treated leachate was concentrated by nanofiltration. While a 70% permeate recovery ratio was kept constant, the rare earth elements concentrations were triplicated under optimum conditions. A flat sheet supported liquid membrane process with a polyvinylidene fluoride (PVDF) support membrane was successfully used to extract REEs from the pre-treated leachate. Of the two extractants evaluated, bis-2-ethylhexyl phosphoric acid (D2EHPA) displayed a higher REE separation efficiency than did di-2,4,4,-trimethylpentyl phosphinic acid (Cyanex 272). However, Cyanex 272 separated Sc more selectively. For direct membrane solvent extraction (MSX) and MSX with pre-concentration, pretreatment pH and D2EHPA concentrations were optimized at values of 1.5% and 15%, respectively. When comparing the results of MSX for direct and pre-concentrated configurations, it was seen that REEs and HREEs recoveries were increased 10% and 30% in MSX with pre-concentration at the end of single-stage MSX. Pre-concentration not only increased the MSX process efficiency but also enabled acid recovery from nanofiltration permeate. A more environmentally friendly and economical process scheme was proposed, including acid recovery from both NF filtrate and post-MSX leaching residue by two different membrane distillation configurations.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Fawzy, SamerOsman, Ahmed I.Farrell, CharlieAl-Muhtaseb, Ala'a H....
10页
查看更多>>摘要：Herein, the aim was to develop an in-depth understanding of the kinetic behaviour of olive tree pruning residue (OTPR), an abundant agricultural waste, during pyrolysis. Thermal analysis at 1, 2, 4, 6 and 10 degrees C.min(-1) was performed using TGA-thermogravimetric analysis, with the results subsequently used to determine the OTPR's kinetic thermal breakdown behaviour. Furthermore, advanced kinetics and technology solutions (AKTS) thermo-kinetic tool was applied to investigate the kinetic behaviour of OTPR and to generate kinetic predictions for various heating configurations. Friedman's method was the main approach used to evaluate the kinetic parameters. For comparison, other established kinetic modelling techniques, such as ASTM-E698 and Flynn-Wall-Ozawa (FWO) methods, were applied. The ASTM-E698 approach yielded an apparent activation energy (E-a) of 172.09 kJ.mol(-1), whereas the FWO method yielded an E-a range from 38 to 172 kJ.mol(-1). Finally, the differential iso-conversional approach yielded E-a values ranging between 85 and 191 kJ.mol(-1). Kinetic predictions were then developed for isothermal, non-isothermal, and stepwise configurations using the kinetic parameters obtained via Friedman's model. The forecasts shed light on optimising production throughput in a variety of reactor configurations. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
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